Thermostatic mixing valve

Abstract

Embodiment thermostatic valves are protected against damage to the wax motor from the leakage of hot water into the valve when the hot water inlet is closed. Embodiments include an improved temperature motive means with fewer parts than conventional valves and with an improved sealing relation between the wax motor/shuttle and the water ports.

We claim: 
     
       1. A thermostatic mixing valve comprising:
 a body, 
 a mixing chamber having a wall located in the body 
 a cold water path comprising a cold water inlet, cold water conduit, a circumferential cold water port, and a circumferential cold water seat on the upper edge of the cold water port, the cold water port and cold water seat located on the wall of the mixing chamber, 
 a hot water path comprising a hot water inlet, hot water conduit, a circumferential hot water port, and a circumferential hot water seat located on the lower edge of the hot water port, the hot water port and hot water seat located on the wall of the mixing chamber below the cold water port and cold water seat, 
 a mixed water path comprising the mixing chamber and a mixed water outlet, 
 a shuttle having on its upper circumference a cold water lip and on its lower circumference a hot water lip, 
 the shuttle having a lumen with a shoulder, 
 the shoulder having an upper surface and a lower surface, 
 a cylindrical wax motor comprising a wax motor stem extending from a wax motor body, the wax motor body further having a wax motor shoulder radially projecting therefrom and defining an upper surface and a lower surface, 
 the wax motor body being axially slideable relative to the shuttle operation of the mixing valve, 
 the wax motor shoulder upper surface in contact with the shuttle shoulder lower surface, 
 the wax motor not connected to the shuttle, 
 a shuttle spring in contact with the shuttle shoulder upper surface and biasing the shuttle toward the wax motor body, and 
 a wax motor spring in contact with the wax motor shoulder lower surface and biasing the wax motor body toward the shuttle. 
 
     
     
       2. The thermostatic mixing valve of  claim 1  wherein the cold water path further comprises a cold water check valve. 
     
     
       3. The thermostatic mixing valve of  claim 1  wherein the hot water path further comprises a hot water check valve. 
     
     
       4. The thermostatic mixing valve of  claim 1  further comprising a motor spring retaining rib attached to the mixing chamber. 
     
     
       5. The thermostatic mixing valve of  claim 1  further comprising a bonnet attached to the body. 
     
     
       6. The thermostatic mixing valve of  claim 5  further comprising a temperature adjustment stem attached to the bonnet.